German Patent Document DE 43 18 080 A1 discloses the use of an at least substantially identically constructed driver's cab structure for different variants of a commercial vehicle. The different vehicle variants being implemented by fitting to the body-in white different cladding parts or by installing a window instead of a cladding part. It is further proposed that the non-load-bearing cladding parts, which are not part of the body-in-white structure, can if required be provided with reinforcements for attaching safety belts and that, in cladding parts designed as hollow sections, these reinforcements can be placed within the hollow section. It is further proposed that guides for sliding doors should be integrated into a cladding part, which requires that the cladding part is cut open.
German Patent Document DE 10 2005 043 698 A1 discloses a side skirt of a motor vehicle body with a box section composed of at least two part-shells, which is reinforced by a structural part in the region of the occupant cell, the structural part being permanently joined to the box section. The structural part comprises a fiber-reinforced plastic part which is supported on at least one of the part-shells of the box section.
From standard motor vehicle production it is further known that bodies-in-white of passenger cars can be adapted to different load levels by building variants of the body-in-white. If this multitude of body-in-white variants is to be avoided, the body-in-white of the passenger car has to be designed in accordance with the heaviest vehicle, i.e., the body-in-white is reinforced as heavy as the heaviest vehicle requires. This means, however, that all lighter vehicles would have a body-in-white that is reinforced to an excessive degree and therefore excessively heavy. For the lighter vehicle variants, this results in increased costs and increased CO2 emissions owing to the unnecessary excess weight of the body-in-white, which is over-dimensioned for such lighter vehicles.
Exemplary embodiments of the present invention are directed to a method for producing a body-in-white of a motor vehicle and a body-in-white for the motor vehicle that reduces the costs of the motor vehicle.
The method according to the invention for producing a body-in-white of a motor vehicle, in particular of a passenger car, involves producing a support structure that is assigned to the body-in-white of the motor vehicle and which comprises at least one support part, providing the support part of the support structure, depending on the variant of the motor vehicle, at least in some regions, with at least one reinforcing part. If the support part is provided with the reinforcing part after the support structure has been produced, this offers the advantage that the number of body-in-white variants for different variants of the motor vehicle is at least significantly reduced, thereby reducing the costs of the body-in-white and the overall costs of the motor vehicle.
With the method according to the invention, platforms that advantageously lower the cost of the motor vehicle can be used even for different variants of the motor vehicle, the bodies-in-white of which have to meet different requirements, and a wide spectrum can be covered in the behavior of the motor vehicle in an accident. At the same time, the number of body-in-white variants can be kept low, or different variants may even be avoided. The method according to the invention offers the further advantage that the body-in-white or the support structure respectively can be designed for the variant that has the lowest weight of all the variants of the motor vehicle. If a variant of the motor vehicle has a higher weight and therefore required a strengthened and reinforced body-in-white or a strengthened and reinforced support structure, this can be achieved with the body-in-white or the support structure designed for the lowest weight by providing the at least one support part of the support structure with the reinforcing part, the reinforcing part being arranged on the support part in a load-level-oriented way, i.e., as a function of a loading in an accident. The reinforcing part is advantageously fitted after the body-in-white or the support structure has been produced.
This loading in an accident is, for example, determined before the support part is provided with the reinforcing part or even before the start or at least before the end of the production of the support structure or the body-in-white, this determination being for example based on simulation, calculation, and/or experiments. Depending on the results obtained in this way, the support part with the reinforcing part is then placed at suitable points, in particular points of high loading.
This allows for a variant control and therefore for a cost reduction and a weight reduction in basic types. With the method according to the invention, it is no longer required to design the body-in-white for the heaviest variant of the motor vehicle, in which case even the lightest variants would have to have a body-in-white designed for the heaviest variants, which would have a detrimental effect on their weight.
The method according to the invention can also be used in derivatives, for example such variants as a coupe, a convertible, a van, a roadster or other variants without a roof or with a roof which can be opened and closed. The cost-reducing effect of the method according to the invention is particularly beneficial if large numbers and many different variants are produced.
Within the framework of the method according to the invention, it may, for example, be provided that joint elements of the support structure or the body-in-white are reinforced with at least one reinforcing part. A plurality of such reinforcing parts is perhaps provided, which are positioned and arranged in a load-level-oriented manner on the support part or the support structure, which may comprise a plurality of such support parts. Such a reinforcing part may for example be supported on the support part.
At this point, it should be noted that the support part is formed, for example, from two part-shells that are joined to each other via respective joining flanges, for example by spot welding and/or bonding or the like, the reinforcing part being supported, for example, on a part-shell which may, for example, be made of sheet metal. It may also be provided that the reinforcing part encompasses a section and for example the major part of the support part or of such a part-shell.
In an advantageous embodiment of the invention, the support part is provided with the reinforcing part after a coating, paint, in particular applied by dip painting, or the like has been applied. If the reinforcing part is, for example, made of a fiber-reinforced plastic material, this offers in the present context the advantage that a plastic matrix of the reinforcing part can then be cured by the heat involved in the painting process, in particular in the cathodic dip painting process. This allows the parallel arrangement of processes, resulting in a time reduction and therefore a further cost reduction for the method, the body-in-white and the motor vehicle as a whole. The fiber-reinforced plastic material may, for example, be a glass fiber-reinforced plastic, a carbon fiber-reinforced plastic or the like.
In a further advantageous embodiment of the invention, a reinforcing part which is at least substantially made of aluminum is provided, the reinforcing part then having a very low specific weight with beneficial effects on the total weight of the support structure and thus of the motor vehicle. This keeps the energy required for the operation of the motor vehicle low, which in the case of a drive unit designed as an internal combustion engine results in low fuel consumption and low CO2 emissions.
It may also be provided that a reinforcing part substantially made of steel is provided. This then is a particularly rigid and stable reinforcing part by means of which the support structure or the support part is reinforced in a particularly efficient manner. If the reinforcing part is made of steel or of sheet metal, it is further possible to optimize the behavior of the support structure or the support part in an accident by at least one bead of the reinforcing part. In this context, it should be noted that, if the reinforcing part is at least substantially made of a fiber-reinforced plastic material, the fibers of the fiber-reinforced plastic material can be oriented to match the loading, thereby adapting the behavior of the support part and thus of the entire support structure in an accident to requirements.
The material of the reinforcing part that is at least substantially made of aluminum is, for example, a higher-strength aluminum material. The material of the reinforcing part that is at least substantially made of steel is, for example, a thermoformed steel, and the material of the reinforcing part that is at least substantially made of a plastic material is, for example, carbon fiber-reinforced patches (CFRP patches).
The at least one reinforcing part is joined to the at least one support part using conventional joining technologies, for example. The reinforcing part may, for example, be bonded and/or riveted to the support part. If the support part is provided with the reinforcing part after the coating process, in particular after cathodic dip painting, bonding is a particularly suitable technology for joining the reinforcing part to the support part, particularly if the reinforcing part is at least substantially made of fiber-reinforced plastic; another suitable method is riveting. When using the bonding technology, an adhesive provided for joining the reinforcing part to the support part can be cured particularly well by the heat involved in the coating process, which saves more time and therefore reduces costs even further. The joining technology has to be adapted to the point of installation and/or to the type and degree of the loading prevailing there.
The invention further includes a body-in-white for a motor vehicle, in particular for a passenger car, and a support structure comprising at least one support part. According to the invention, the support part can, depending on the variant of motor vehicle, be provided with at least one reinforcing part at least in some regions, wherein the support part can advantageously be provided with the reinforcing part after the support structure has been produced. Advantageous further developments of the method according to the invention should be considered as advantageous further developments of the body-in-white according to the invention and vice versa.
The body-in-white according to the invention likewise allows for a late variant control and at least for a reduction of the number of body-in-white variants across different variants of the motor vehicle. According to the invention, the reinforcing part is fitted after the body-in-white or the support structure respectively has been produced and does not have to be fitted during the production of the body-in-white. This significantly standardizes the body-in-white assembly of different motor vehicle variants, resulting in a noticeable time and cost reduction for the body-in-white and thus for the motor vehicle as a whole.
Further advantages, features and details of the invention can be derived from the following description of several preferred embodiments and from the drawing. The features and feature combinations mentioned in the above description and the features and feature combinations described below in the description of the figures and/or shown in the figures only can be used not only in the specified combination, but also in other combinations or individually without exceeding the scope of the invention.